Chemical senses such as taste and olfaction play an important role in human life and their loss in many diseases or as a consequence of chemotherapy contributes significantly to the deterioration of quality of life. Even though the role of pheromones in humans is still poorly understood, recent progress has demonstrated the existence of human pheromones and suggests that their role has been underestimated in the past. The fruit fly Drosophila melanogaster is arguably the best studied multicellular animal and provides many practical advantages for the study of chemical senses. We have discovered two male-specific proteins expressed in chemosensory organs suggesting that they may be involved in the recognition of female pheromones by males. The function of the cells in which those two proteins are expressed will be tested by using directed cell ablation. To test the function of the proteins themselves we will generate null mutants and determine their response to female pheromones. The long-term goal of this work is, through the use of Drosophila as a model system, to gain a greater understanding of pheromone response with likely implications for our understanding of human chemical senses and response to pheromones in particular.